Treadmill Intervals

treadmill
an exercise device consisting of an endless belt on which a person can walk or jog without changing place
A job or situation that is tiring, boring, or unpleasant and from which it is hard to escape
a mill that is powered by men or animals walking on a circular belt or climbing steps
An exercise machine, typically with a continuous belt, that allows one to walk or run in place
a job involving drudgery and confinement
A device formerly used for driving machinery, consisting of a large wheel with steps fitted into its inner surface. It was turned by the weight of people or animals treading the steps

intervals
An intermission separating parts of a theatrical or musical performance
(interval) the distance between things; "fragile items require separation and cushioning"
An intervening time or space
time interval: a definite length of time marked off by two instants
A pause; a break in activity
(interval) a set containing all points (or all real numbers) between two given endpoints